Fluid systems used in mechanical devices for lubricating purposes or for transmitting power, become contaminated by wear particles from the mechanical components of the device during the life of the machine. Such particles are derived from wear in bearings, gears and other metallic components subject to frictional forces and from components that fracture under excessive stress. The detection of the presence of such debris, and particularly the amount of such debris, has been used to determine the degree of wear occurring in the device and also to predict impending failure by the presence of large amounts of debris. One such apparatus is described in U.S. patent application Ser. No. 07/544,941, filed on Jun. 28, 1990 which is referenced above, and also in U.S. Pat. Nos. 3,878,103 and 3,686,926. This application and these patents describe electro-mechanical devices for detecting the presence of debris in the system and measuring the amount of debris present. These devices all contain a screen for trapping large particles present in the fluid and incorporate with the screen a method of detecting the presence of debris particles. In the issued patents cited, debris is detected when an electrically conductive particle comes in contact with the metallic screen and completes the electrical circuit connected to the wire mesh of the screen. In the U.S. patent application cited above, there is disclosed an apparatus for using the inductive properties of a coil embedded in the screen to measure the amount of debris accumulated. In the two U.S. patents cited, the presence of large amounts of debris is sensed, but progressive, incremental accumulation and the total amount of accumulation cannot be suitably measured. Thus, the sensor often fails to accurately indicate an impending failure of the system and cannot indicate a rate of accumulation which would forecast the impending failure. The U.S. patent application cited will measure debris accumulation and accumulation rate but the sensitivity of the device is limited.